JP2007222837A - Method of producing coating film and coating apparatus using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the occurrence of fine cracks on the surface of an electrode in applying a coating liquid on a belt-like support and drying it and to improve productivity. <P>SOLUTION: In the method of producing the coating film which includes a coating step for applying the coating liquid on the belt-like support 2 and a drying step for drying the belt-like support 2 coated with the coating liquid in a drying room, the drying step includes a first drying step for drying until the water content reaches a critical water content which is a water content of the coating liquid in a point of time when the diffusion rate in the coating liquid on almost the whole surface of the coating liquid becomes smaller than the rate of the vaporization of the liquid from the liquid surface, and a second drying step for drying hereafter, wherein the first drying step has a heat transfer rate higher than that in the second drying step. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for producing a coating film excellent in productivity and reliability, and a coating apparatus using the method.

  A conventional coating film is obtained by applying a coating solution on the surface of a belt-like support and then drying it. Depending on the dry state of the coating solution, the adhesive force between the belt-like support and the coating material, the binding force between the coating materials, and the like are determined, which is a factor that greatly affects the characteristics of the coating film.

  Conventionally, in the drying process, after applying a liquid coating solution on the belt-like support, the drying was performed with an emphasis on drying quickly. Fine cracks and the like are generated on the surface, which impairs the function as a coating film.

  Therefore, in the conventional drying process, to a certain extent, gradually increase the heat transfer rate, which is one index representing the strength of drying, and then further increase the temperature or increase the amount of hot air, Drying methods such as further increasing the heat transfer rate, or gradually decreasing the heat transfer rate to a certain extent, and then lowering the temperature or reducing the amount of hot air to further reduce the heat transfer rate The method was used.

For example, Patent Document 1 and Patent Document 2 are known as prior art document information related to the invention of this application.
JP 2003-205264 A JP 2004-28495 A

  In the above conventional manufacturing method, the heat transfer rate applied to the coating liquid is gradually increased from a low heat transfer rate to a high heat transfer rate, or is gradually decreased from a high heat transfer rate to a low heat transfer rate. The coating solution was dried by going. When the coating liquid is dried by these methods, fine cracks are generated on the surface of the coating film, or productivity is lowered.

  Therefore, the present invention aims to improve productivity while preventing fine cracks from being generated on the surface of the coating film when the coating liquid applied on the belt-like support is dried.

  In order to achieve this object, the present invention is designed such that when a coating solution is applied on a belt-like support and then dried in a drying chamber, the diffusion rate in the coating solution on almost the entire surface of the coating solution is changed from the surface of the solution. The heat transfer rate given to the coating solution in the first drying step, which is the drying step until the moisture content of the coating solution reaches the limit moisture content at the time when it becomes smaller than the evaporation rate of the solution, is The coating film manufacturing method is higher than the heat transfer rate applied to the coating liquid in the second drying process, which is a drying process after the coating liquid reaches the limit moisture content.

  The method for producing a coating film of the present invention produces a coating film in which fine cracks are not generated on the surface of the coating film without changing the productivity by changing the drying conditions with the critical moisture content as a boundary. It is something that can be done.

(Embodiment 1)
Hereinafter, the drying method after applying the coating liquid to the coating apparatus and the continuously running belt-like support in Embodiment 1 of the present invention will be described with reference to the drawings.

  First, the coating apparatus 1 shown in FIG. 1 will be described. The coating apparatus 1 has an unwinding roll 5, a roll 8, a backup roll 7, a roll 9, a roll 10, and a winding roll 6 in order to continuously run the belt-like support 2.

  Further, in FIG. 1, only the minimum number of rolls necessary for continuously running the belt-like support 2 is described, but the number and types of rolls are not particularly limited.

  The coating apparatus 1 has a coating machine 3 and a backup roll 7 for coating a coating liquid (hereinafter not shown) on the belt-like support 2, and the backup roll 7 depends on the coating machine 3 used. It may not be necessary.

  As the coating machine 3, a doctor blade coater, a die coater, a gravure coater, a micro gravure coater, a roll coater, or the like can be used, but the apparatus is not particularly limited, and an apparatus that can apply a coating solution onto the belt-like support 2. Any other device may be used as long as it is.

  Further, the coating device 1 includes a drying device 4 for drying the coating solution coated on the belt-like support 2.

  Desirably, the drying apparatus 4 has two or more drying chambers 11 capable of independently controlling the drying conditions, and has three or more drying chambers 11 capable of independently controlling the drying conditions. If so, it is more desirable.

  In the drying chamber 11, at least one of a dryer using a mechanism based on conduction heat transfer, a dryer using a mechanism based on convection heat transfer, and a dryer using a mechanism based on heat dissipation heat transfer as a dryer. Has a dryer.

  As a dryer using a mechanism based on conduction heat transfer, a dryer such as a cylindrical dryer or a drum dryer can be used. However, the type of the dryer is not particularly limited, and a mechanism based on conduction heat transfer is used. Any other dryer may be used as long as it is a dryer.

  As a dryer using a mechanism by convection heat transfer, a hot air dryer or the like can be used, but the type of the dryer is not particularly limited, and if it is a dryer using a mechanism by convection heat transfer, Any other dryer may be used.

  The hot air dryer includes a parallel flow operation in which hot air flows in the same direction as the traveling direction of the belt-like support 2, a countercurrent operation in which hot air flows in a direction opposite to the travel direction of the belt-like support 2, and the belt-like support 2. Although an operation such as an operation of flowing hot air at right angles to the belt-like support 2 can be performed from the surface side on which the coating liquid is applied or / and the surface side where the coating liquid is not applied, the direction of flowing hot air is particularly limited. However, in order to dry the coating liquid applied on the belt-like support 2, an operation of flowing hot air from one or more directions may be performed.

  As a dryer using a mechanism by radiant heat transfer, a near-infrared dryer, a mid-infrared dryer, a far-infrared dryer, an infrared dryer, etc. can be used, but the type of dryer is not particularly limited. Any other dryer may be used as long as the dryer uses a mechanism based on radiant heat transfer.

  Further, the inside of the drying chamber 11 is preferably filled with a gas such as dry air, nitrogen gas, or argon gas having a relative humidity of 30% or less. However, the type of gas in the drying chamber 11 is not particularly limited. As long as the relative humidity is 30% or less, any other gas can be used as a desirable condition.

  If a gas having a relative humidity of 30% or less is used, the saturated humidity of the gas (kg / kg / dry air) and the drying, which is a driving force when drying the coating solution applied on the belt-like support 2 by the coating machine 3, are dried. Since the difference in the humidity (kg / kg · dry air) of the gas in the chamber 11 becomes large, the drying rate can be increased.

  However, the drying chamber 11 is not necessarily filled with gas, and the gas in the drying chamber 11 may be evacuated using a vacuum pump or the like. By performing the evacuation, the component evaporated from the coating solution can be removed from the drying chamber 11, so that the drying speed can be increased.

  The width of the dryer disposed in the drying chamber 11 is preferably wider than the width of the belt-like support 2. By making the width of the dryer arranged in the drying chamber 11 wider than the width of the belt-like support 2, a large amount of heat can be generated even under drying conditions with a low heat transfer rate per unit area. It can give to the coating liquid apply | coated by the coating machine 3 on the top, and can dry a coating liquid in a short time.

  The length of the drying chamber 11 is not particularly specified, but it is more desirable to define the drying chamber 11 with the following length, and it is more desirable to form a coating film that is soft, free from cracks and peeling, and has a smooth surface. Obtainable.

  In the case of having three drying chambers 11 that can control drying conditions independently, the drying chamber 11 in which the belt-like support 2 supplied from the unwinding roll 5 first enters is the first drying chamber. 11a, the next drying chamber 11 is the second drying chamber 11b, and finally the drying chamber 11 through which the belt-like support 2 passes is the third drying chamber 11c. The length of the drying chamber 11a may be 1/10 or more, the length of the second drying chamber 11b may be 4/5 or less, and the length of the third drying chamber 11c may be 1/10 or more.

  Even in the drying apparatus 4 having four or more drying chambers 11 capable of independently controlling the drying conditions, by considering a plurality of continuous drying chambers 11 as zones, the three drying zones are provided. The length of the first drying zone is 1/10 or more, the length of the second drying zone is 4/5 or less, and the length of the third drying zone is 1/0 of the length of the drying device 4. What is necessary is just to make it 10 or more.

  Here, how to separate the drying zones in the drying apparatus 4 having four or more drying chambers 11 capable of independently controlling the drying conditions will be described.

  First, the first drying zone is a drying chamber continuous from the first drying chamber 11a, and dries the coating liquid applied on the belt-like support 2 at a heat transfer rate higher than that of the previous drying chamber 11. This is an assembly of drying chambers 11 having the ability.

  The second drying zone is a drying chamber 11 continuous from the final drying chamber 11 of the first zone, and is applied onto the belt-like support 2 at a heat transfer rate equal to or lower than the final drying chamber 11 of the first zone. Ability to dry the coating liquid applied on the belt-like support 2 at a heat transfer rate lower than that of the previous drying chamber 11 continuously with the drying chamber 11 having the ability to dry the applied coating liquid It is an assembly of the drying chamber 11 having

  Further, the third drying zone is a drying chamber 11 continuous from the final drying chamber 11 of the second zone, and is on the belt-like support 2 at a heat transfer rate higher than that of the final drying chamber 11 of the second drying zone. It is an aggregate of all the drying chambers 11 after the drying chamber 11 having the ability to dry the coating liquid applied to the.

  In addition, about the drying chamber 11 of a 1st zone, the drying chamber 11 which had the capability to dry the coating liquid apply | coated on the strip | belt-shaped support body 2 below the heat transfer rate of the drying chamber 11 immediately before 1st is used. Even if included, the coating liquid is applied onto the belt-like support 2 by the coating machine 3 and dried using the drying device 4 having the first drying zone, the second drying zone, and the third drying zone. By doing so, it is possible to obtain a coating film that is soft, free from cracks and peeling, and has a smooth surface.

  The drying chamber 11 in the second zone includes the drying chamber 11 having the ability to dry the coating solution applied on the belt-like support 2 at a rate higher than the heat transfer rate of the previous drying chamber 11 intermittently. However, the coating liquid is applied onto the belt-like support 2 by the coating machine 3 and dried using the drying device 4 having the first drying zone, the second drying zone, and the third drying zone. Thus, it is possible to obtain a coating film that is soft, free from cracks and peeling, and has a smooth surface.

  Further, in the first drying chamber 11a or the drying chamber 11 in the first zone, the moisture content of the coating solution applied on the belt-like support 2 by the coating machine 3 = (solvent weight in the coating solution / inside of the coating solution). It is desirable to provide a dryer that can be dried to a limit moisture content that is a moisture content at the boundary between the constant rate drying period and the reduced rate drying period.

  In the first drying chamber 11a or the drying chamber 11 in the first zone, a dryer capable of drying the coating liquid applied on the belt-like support 2 with the coating machine 3 to the limit moisture content is provided. If it is, the coating liquid is coated on the belt-like support 2 by the coating machine 3 and dried by the drying device 4 to obtain a coating film that is soft, has no cracks or peeling, and has a smooth surface.

  Here, the expression of water content in the present invention will be described.

  The moisture content is not limited to the case where the solvent is water, but is expressed as the moisture content even when the solvent is water, an organic solvent, or any other liquid.

  Further, it is desirable to use a dryer using a mechanism by radiant heat transfer in the first drying chamber 11a or the drying chamber 11 in the first zone. If a dryer using a mechanism based on radiant heat transfer is used in the first drying chamber 11a or the drying chamber 11 in the first zone, a dryer using a mechanism based on conductive heat transfer or a mechanism based on convective heat transfer is used. Since a large amount of heat can be applied to the coating liquid applied by the coating machine 3 on the belt-like support 2 relatively easily than the dryer, the initial drying can be performed in a short time.

  In addition, it is desirable to use a dryer using a mechanism by radiant heat transfer in the third drying chamber 11c or in the drying chamber 11 in the third zone. If a dryer using a mechanism based on radiant heat transfer is used in the third drying chamber 11c or the dryer chamber 11 in the third zone, a dryer using a mechanism based on conductive heat transfer or a mechanism based on convective heat transfer is used. Since a larger amount of heat can be applied to the coating liquid applied by the coating machine 3 on the belt-like support 2 than the dryer, the coating liquid applied by the coating machine 3 on the belt-like support 2 is dried. Residual moisture content in the coating film obtained by drying with the apparatus 4 = (weight of solvent contained in the coating film) / (weight of coating film) is shortened to finish drying to the desired residual moisture content. Can be done in time.

  Here, the expression of the residual moisture content in the present invention will be described. The residual moisture content is not limited to the case where the solvent is water, but is expressed as the residual moisture content even when the solvent is water, an organic solvent, or any other liquid.

  Further, it is desirable that the coating device 1 has a mechanism for applying tension to the belt-like support 2 by using a device such as a powder clutch or a dancer, but the device for applying the tension is particularly limited. Instead, any other device can be used as long as it is a device for applying tension to the belt-like support 2.

  Furthermore, it is desirable that the coating apparatus 1 has a nip roll or the like in order to change the magnitude of the tension applied to the belt-like support 2 in an arbitrary range. In particular, the tension applied to the belt-like support 2 in an arbitrary range. The mechanism for changing the size of the belt is not limited, and any other mechanism may be used as long as it is a mechanism for changing the magnitude of the tension applied to the belt-like support 2 within an arbitrary range. be able to.

  It is desirable that the coating apparatus 1 has a mechanism that can vary the supply speed of the belt-like support 2. Further, the supply speed of the belt-like support 2 is set to a time period from 5 seconds to 120 seconds from when the belt-like support 2 enters the first drying chamber 11a until it comes out of the second drying chamber 11b or the second drying zone. It is more desirable to have a mechanism that can be controlled as follows.

  In addition, there is a mechanism capable of controlling the supply speed of the belt-like support 2 from 10 seconds to 180 seconds from when the belt-like support 2 enters the first drying chamber 11a until it comes out from the final drying chamber 11x. If so, it is more desirable.

  The supply speed of the belt-like support 2 is set to 5 seconds or more and 120 seconds or less after the belt-like support 2 enters the first drying chamber 11a until it comes out of the second drying chamber 11b or the second drying zone. The controllable mechanism or / and the supply speed of the belt-like support 2 is the time from 10 seconds to 180 seconds from the time when the belt-like support 2 enters the first drying chamber 11a until it comes out from the final drying chamber 11x. If it has a mechanism that can be controlled, a coating solution is applied onto the belt-like support 2 by a coating machine 3 and dried by a drying device 4 so that the coating is soft, free of cracks and peeling, and has a smooth surface. A film can be obtained in a short time.

  Next, using the coating apparatus 1, the coating liquid is applied onto the belt-like support 2 by the coating machine 3, the coating liquid applied onto the belt-like support 2 is dried by the drying device 4, and the coating film is formed. A method of obtaining will be described.

  In Embodiment 1 of the present invention, a method for producing a coating film of a polarizable electrode will be described as a specific example. However, the application field of the present invention is not particularly limited, and the same method as in Embodiment 1 is used. The present invention can be used in any other field as long as it is an industrial field using a coating film capable of obtaining a coating film.

  As the coating solution, a solution in which a solute such as a polymer material or a polymer resin is dissolved in a solvent such as water or an organic solvent can be used. However, the type of the solvent and the solute is not particularly limited, and any solvent can be used. And solutes can be used.

  Moreover, you may use the solvent which mixed the several solvent as a solvent. Furthermore, a solute obtained by mixing a plurality of solutes may be used.

  Moreover, an emulsion can be used as a coating liquid. The emulsion is an O / W type emulsion prepared by gradually adding an aqueous phase to an oil phase containing an emulsifier, or a W / O type prepared by gradually adding an oil phase to an aqueous phase containing an emulsifier. Emulsions include O / W / O type emulsions and W / O / W type emulsions that are multilayer emulsions prepared by performing these operations a plurality of times, but the type of emulsion is not particularly limited. Any other emulsion can be used as long as it exists.

  Furthermore, a dispersion liquid of particles can be used as the coating liquid. As the liquid for dispersing the particles, water, an organic solvent, or the like can be used. However, the type of the liquid is not particularly limited, and any other liquid may be used as long as it is a liquid.

  Further, a liquid in which particles are dispersed may be a liquid in which a plurality of liquids are mixed. Furthermore, as the particles dispersed in the liquid, carbon materials, ceramic materials, polymer materials, polymer resins, pharmaceutical materials, food materials, pigments, metals, etc. can be used, but the types of particles are not particularly limited. Any particle can be used as long as it is a particle.

  Here, as the coating liquid, a solution, an emulsion, a dispersion of particles, and the like can be used, but the type of the liquid is not particularly limited, and any other liquid can be used.

  Further, a solution, an emulsion, or a dispersion of particles may be used alone as a coating solution, but a mixture of one or more types of solutions and one or more types of emulsions, one or more types of solutions, and one or more types of particles. A liquid mixture of the above-mentioned dispersion liquid and a liquid mixture of one or more kinds of emulsions and one or more kinds of particle dispersions may be used.

  Furthermore, a mixture of one or more types of solutions, one or more types of emulsions, and a dispersion of one or more types of particles may be used.

  Further, the moisture content of the coating liquid before coating on the belt-shaped support 2 by the coating machine 3 varies depending on the type of coating liquid used and the type of coating film to be used. The water content of the coating liquid before coating by the coating machine 3 is not limited.

  In the first embodiment, a polarizable electrode in which activated carbon and acetylene black, which are carbon materials, are dispersed in a solution obtained by dissolving a binder that is a polymer resin in water as a coating solution, and further an emulsion of polytetrafluoroethylene is mixed. The liquid was used.

  In Embodiment 1, the water content of the polarizable electrode solution, which is a coating solution before being coated on the belt-like support 2 by the coating machine 3, is 2.5.

  Although metal foil, a film, paper, etc. can also be used as the strip | belt-shaped support body 2, The kind of strip | belt-shaped support body 2 is not specifically limited, All the other types of strip-shaped support bodies 2 can be used.

  In Embodiment 1 of the present invention, an aluminum etching foil having a thickness of 20 μm obtained by roughening an aluminum foil by etching treatment was used as the belt-like support 2.

  As the applicator 3, the type of the applicator 3 is not particularly limited as long as the applicator 3 can apply the coating liquid on the belt-like support 2 with a desired thickness, and any applicator 3 is used. be able to.

  Here, about the thickness which apply | coats a coating liquid on the strip | belt-shaped support body 2, the thickness of a coating film can be determined according to the kind of target coating film. In the first embodiment, coating was performed so that the thickness of the coating material layer of the coating film after drying was 75 μm.

  Further, as the applicator 3, the applicator 3 that applies the coating liquid on one side of the belt-like support 2 may be used, or the applicator 3 that applies the coating liquid on both sides of the belt-like support 2 simultaneously. You may use.

  In Embodiment 1, the thickness of the polarizable electrode layer of the polarizable electrode that is the coating film after drying the polarizable electrode liquid that is the coating liquid on the 20 μm aluminum etching foil that is the belt-like support 2 is the thickness of the polarizable electrode layer. A die coater was used as the applicator 3 so as to have a thickness of 75 μm, and coating was performed on one side.

  A coating film is obtained by drying the coating solution coated on the belt-like support 2 by the coating machine 3 with the drying device 4. Desirably, the drying device 4 for drying the coating liquid applied by the coating machine 3 on the belt-like support 2 has two or more drying chambers 11 capable of independently controlling the drying conditions.

  If the drying apparatus 4 having two or more drying chambers 11 capable of independently controlling the drying conditions is used, until the moisture content of the coating liquid applied on the belt-like support 2 reaches the limit moisture content The initial drying can be performed in a short time. Alternatively, it is assumed that finish drying can be performed in a short time when the moisture content of the coating solution applied on the belt-like support 2 is equal to or lower than the limit moisture content.

  Moreover, the drying apparatus 4 for drying the coating liquid applied by the coating machine 3 on the belt-like support 2 has at least three drying chambers 11 capable of independently controlling the drying conditions. More desirable.

  If the drying apparatus 4 having three or more drying chambers 11 capable of independently controlling the drying conditions is used, until the moisture content of the coating liquid applied on the belt-like support 2 reaches the limit moisture content The initial drying of the solvent can be performed in a short time, and the evaporation rate of the solvent from the surface of the coating solution during the period when the moisture content of the coating solution is near the limit moisture content is less than the diffusion rate of the solvent in the coating film. By drying the coating solution under dry conditions, it is possible to obtain a coating film that is soft, free of cracks and peeling, has a smooth surface, and has a short drying finish to the desired residual moisture content. It can be done in time.

  Here, the drying conditions of the dryer provided in the drying device 4 for drying the coating solution applied on the belt-like support 2 by the coating machine 3 will be described.

  First, drying in the case where the drying device 4 for drying the coating solution applied on the belt-like support 2 by the coating machine 3 has two drying chambers 11 capable of independently controlling the drying conditions. A method will be described.

  In the drying apparatus 4 having two drying chambers 11 capable of independently controlling the drying conditions, in the first drying chamber 11a, the coating liquid applied on the belt-like support 2 by the coating machine 3 is used. It is desirable to perform drying for a period of time until the moisture content is 150% or less of the critical moisture content.

  In addition, the type of dryer used at that time is at least one of a dryer using a mechanism based on conduction heat transfer, a dryer using a mechanism based on convection heat transfer, and a dryer using a mechanism based on radiant heat transfer. More than one dryer can be used.

  In the first drying chamber 11a, drying is performed for a period until the moisture content of the coating solution applied on the belt-like support 2 by the coating machine 3 is 150% or less of the critical moisture content. It is desirable to increase the heat transfer rate given per unit area of the coating liquid as much as possible.

  To increase the heat transfer rate applied per unit area of the coating liquid as much as possible to the coating liquid on the belt-like support 2 is different depending on the type of the target coating film, although the appropriate temperature and air volume are different. It is shown that the heat transfer rate given per unit area of the coating liquid is increased by the high temperature and large air volume within the range in which the temperature and the air volume applied to the film do not affect the properties of the coating film.

  By increasing the heat transfer rate given per unit area of the coating liquid as much as possible, the initial drying is performed until the moisture content of the coating liquid coated on the belt-like support 2 is in the range of 150% or less of the limit moisture content. It can be done in a short time.

  In the drying apparatus 4 having two drying chambers 11 that can independently control the drying conditions, the second drying chamber 11b contains the coating solution applied on the belt-like support 2 by the coating machine 3. It is desirable to perform drying for a period until the moisture content reaches a desired residual moisture content from a range of 150% or less of the critical moisture content.

  The type of dryer used at that time is at least one of a dryer using a mechanism based on conduction heat transfer, a dryer using a mechanism based on convection heat transfer, and a dryer using a mechanism based on radiation heat transfer. The dryer can be used.

  In the second drying chamber 11b, it is more desirable to dry the period during which the moisture content of the coating liquid is the limit moisture content.

  Further, in the second drying chamber 11b, in the period from when the moisture content of the coating liquid applied on the belt-like support 2 by the coating machine 3 becomes 150% or less of the critical moisture content to the desired residual moisture content, The heat transfer rate given per unit area of the coating solution to the coating solution on the support 2 is determined by the evaporation rate of the solvent in the coating solution on the surface of the coating solution coated on the belt-like support 2. It is desirable to set it to be lower than the diffusion rate of the solvent inside.

  The heat transfer rate given per unit area of the coating solution to the coating solution on the belt-like support 2 is such that the evaporation rate of the solvent in the coating solution on the surface of the coating solution is less than the diffusion rate of the solvent in the coating solution. By drying the coating solution applied on the belt-like support 2 under the drying conditions set to be, a coating film that is soft, free from cracks and peeling, and has a smooth surface can be obtained.

  Here, the drying apparatus 4 used in Embodiment 1 is demonstrated.

  In the first embodiment, in order to dry a polarizable electrode solution, which is a coating solution applied by a die coater, which is a coating machine 3, on an aluminum etching foil obtained by roughening aluminum, which is a belt-like support 2, by etching. The coating apparatus 1 having two drying chambers 11 capable of independently controlling the drying conditions was used.

  In the first drying chamber 11 a according to the first embodiment, a hot air dryer that blows hot air in a direction opposite to the traveling direction of the belt-like support 2 and a coating machine 3 on the belt-like support 2. A hot air dryer is provided that applies hot air to the belt-like support 2 at a right angle from the surface opposite to the surface on which the liquid is applied.

  Further, in the second drying chamber 11b in the first embodiment, hot air is applied at right angles from the surface of the belt-like support 2 on which the coating liquid is applied by the coating machine 3 and from both sides of the opposite surface. The hot air dryer which supports 2 with a hot air is provided.

  As for the heat transfer rate, it is desirable to obtain the heat transfer rate per unit area of the coating liquid applied on the belt-like support 2, but it is actually difficult to measure the heat transfer rate per unit area of the coating liquid. Therefore, in Embodiment 1, the heat transfer rate per unit area supplied by the dryer is determined by calculation.

Here, the specific drying conditions of the dryer used in Embodiment 1 will be described. The hot air dryer in the first drying chamber 11a includes a hot air dryer that blows hot air in a direction opposite to the traveling direction of the belt-like support 2, and a coating liquid by the coater 3 on the belt-like support 2. Both of the hot air dryers that apply hot air at a right angle to the belt-like support 2 from the surface opposite to the surface on which the coating is applied are devices having twice the coating width of the coating liquid applied on the belt-like support 2. The coating liquid (not shown) was given heat by hot air with a temperature of 80 ° C. and a wind speed of 1 m / s. The heat transfer rate supplied per unit area by the hot air dryer determined by calculation is 2500 J / (m ² · s).

The hot air dryer in the second drying chamber 11b has a device width twice the coating width of the coating liquid applied on the belt-like support 2, and the hot air dryer has a temperature of 50 ° C. The amount of heat was applied to the coating solution by hot air having a wind speed of 1 m / s. The heat transfer rate supplied per unit area by the hot air dryer determined by calculation is 1200 J / (m ² · s).

  Here, the critical moisture content will be described.

  In the case where the coating liquid is dried at a constant heat transfer rate, it is generally known that there are three drying periods: a preheating period, a constant rate drying period, and a reduced rate drying period. And when the moisture content of a coating liquid reaches a limit moisture content, it is known to transfer from a constant rate drying period to a decreasing rate drying period.

  In addition, various phenomena observed before and after the limit moisture content caused by shifting from the constant rate drying period to the decreasing rate drying period when the moisture content of the coating liquid reaches the limit moisture content will be described.

  First, when the moisture content of the coating solution is higher than the limit moisture content, the evaporation rate of the solvent on the coating solution surface is slower than the diffusion rate of the solvent in the coating solution in the coating solution, and the surface of the coating solution Drying is progressing in an evaporation-controlled state, and the surface of the coating liquid is wet. When the water content of the coating liquid is higher than the limit water content, the surface temperature of the coating liquid is kept at a constant temperature substantially equal to the wet bulb temperature of air.

  Next, when the moisture content of the coating solution is lower than the limit moisture content, the diffusion rate of the solvent in the coating solution is slower than the evaporation rate of the solvent on the surface of the coating solution in the coating solution. Since the drying is progressing in a state where the internal diffusion rate of the solvent is controlled, the speed of the solvent movement from the inside of the coating liquid cannot keep up with the evaporation speed of the coating liquid on the surface of the coating liquid. It is in a state of being. Further, when the moisture content of the coating liquid is lower than the limit moisture content, the surface temperature of the coating liquid gradually increases.

  Therefore, in the drying process, the moisture content of the coating solution at the time when the diffusion rate of the solvent in the coating solution on almost the entire surface of the coating solution becomes smaller than the evaporation rate of the solvent from the surface of the coating solution is defined as the critical moisture content.

  Here, how to determine the limit moisture content of the coating solution applied on the belt-like support 2 will be described.

  As a method for determining the limit moisture content of the coating solution, the drying rate of the coating solution is continuously measured, and the moisture content when the drying rate starts to decrease can be set as the limit moisture content.

  In addition, the surface temperature of the coating liquid can be continuously measured, the moisture content at the time when the surface temperature of the coating liquid starts to rise can be used as the limiting moisture content, and the glossiness of the coating liquid surface can be continuously measured, The moisture content at the time when the glossiness of the coating liquid surface starts to change can be made the critical moisture content.

  Furthermore, as a simple method, by touching the surface of the coating liquid, it can be determined whether the surface of the coating liquid is dry or not, and the moisture content at the time of starting to dry can be set as the limit moisture content.

  However, there is no particular limitation on how to determine the limit moisture content, and it is possible to confirm that the drying period of the coating liquid has shifted from the constant rate drying period to the reduced rate drying period. Any method for determining the limit moisture content by any other method can be used.

  Here, the limit water content of the polarizable electrode solution used in the first embodiment is 1.5, and the water content of the coating solution in the first drying chamber 11a is 1.65 which is 110% of the limit water content. And dried in the second drying chamber 11b so that the residual moisture content of the coating solution was 2%.

(Embodiment 2)
Hereinafter, only the points different from the first embodiment will be described with reference to the drawings with respect to the coating apparatus and the drying method after coating the coating liquid on the continuously running belt-like support 2 in the second embodiment of the present invention.

  In the second embodiment, in order to dry the polarizable electrode solution, which is a coating solution applied by a die coater, which is a coating machine 3, on an aluminum etching foil obtained by roughening aluminum, which is a belt-like support 2, by etching. The drying apparatus 4 used was the coating apparatus 1 having three drying chambers 11 capable of independently controlling the drying conditions.

  First, in the drying apparatus 4 having three drying chambers 11 capable of independently controlling the drying conditions, in the first drying chamber 11a, coating applied on the belt-like support 2 by the coating machine 3 It is desirable to perform the drying for a period in which the water content of the liquid is in the range of 80% to 150% of the limit water content. In addition, the type of dryer used at that time is at least one of a dryer using a mechanism based on conduction heat transfer, a dryer using a mechanism based on convection heat transfer, and a dryer using a mechanism based on radiant heat transfer. More than one dryer can be used.

  Further, in the first drying chamber 11a, the belt-like support is used in a drying period in which the moisture content of the coating solution applied onto the belt-like support 2 by the coating machine 3 is in the range of 80% to 150% of the critical moisture content. It is desirable to increase the heat transfer rate given per unit area of the coating liquid as much as possible with respect to the coating liquid on 2.

  Here, with respect to the coating liquid on the belt-like support 2, increasing the heat transfer rate given per unit area of the coating liquid as much as possible varies depending on the type of target coating film and the appropriate temperature and air volume. It shows that the heat transfer rate given per unit area of the coating liquid is increased by the high temperature and the large volume of the air that the temperature applied to the coating liquid and the air volume do not affect the properties of the coating film. Yes.

  Thus, by increasing the heat transfer rate given per unit area of the coating liquid as much as possible, the moisture content of the coating liquid coated on the belt-like support 2 is in the range of 80% to 150% of the limit moisture content. It is assumed that the initial drying which is the drying of can be performed in a short time.

  Further, in the drying apparatus 4 having three drying chambers 11 capable of independently controlling the drying conditions, in the second drying chamber 11b, coating applied on the belt-like support 2 by the coating machine 3 It is desirable to perform drying for a period of time until the water content of the liquid is in the range of 80% or more and 150% or less of the limit water content to a water content of 95% or less of the limit water content.

  The type of dryer used at that time is at least one of a dryer using a mechanism based on conduction heat transfer, a dryer using a mechanism based on convection heat transfer, and a dryer using a mechanism based on radiation heat transfer. The dryer can be used.

  In the second drying chamber 11b, it is further desirable to dry a period in which the moisture content of the coating liquid is the limit moisture content.

  In the second drying chamber 11b, the moisture content of the coating liquid applied on the belt-like support 2 by the coating machine 3 is in the range of 80% to 150% of the critical moisture content, and the moisture content of 95% or less of the critical moisture content. In the coating period on the surface of the coating liquid applied on the belt-like support 2, the heat transfer rate given per unit area of the coating liquid to the coating liquid on the belt-like support 2 during the drying period until It is desirable to set the evaporation rate of the solvent to be equal to or lower than the diffusion rate of the solvent in the coating solution.

  The heat transfer rate given per unit area of the coating solution to the coating solution on the belt-like support 2 is such that the evaporation rate of the solvent in the coating solution on the surface of the coating solution is less than the diffusion rate of the solvent in the coating solution. Is set so that the coating liquid applied on the belt-like support 2 is softened by drying with the drying device 4 having three drying chambers 11 capable of independently controlling the drying conditions, A coating film having a smooth surface without cracking or peeling can be obtained.

  In the drying apparatus 4 having three drying chambers 11 that can independently control the drying conditions, in the third drying chamber 11c, the coating solution applied on the belt-like support 2 by the coating machine 3 is used. It is desirable to perform drying for a period from the moisture content of 95% or less of the critical moisture content to the desired residual moisture content.

  In addition, the type of dryer used at that time is at least one of a dryer using a mechanism based on conduction heat transfer, a dryer using a mechanism based on convection heat transfer, and a dryer using a mechanism based on radiant heat transfer. More than one dryer can be used.

  Further, in the third drying chamber 11c, in the period from the moisture content of 95% or less of the moisture content of the coating solution applied on the belt-like support 2 by the coating machine 3, to the desired residual moisture content, It is desirable to increase the heat transfer rate applied per unit area of the coating liquid as much as possible to the coating liquid on the body 2.

  To increase the heat transfer rate applied per unit area of the coating liquid as much as possible to the coating liquid on the belt-like support 2 is different depending on the type of the target coating film, although the appropriate temperature and air volume are different. To increase the heat transfer rate per unit area of the coating liquid by applying a high temperature and a large air volume within a range where the temperature and air volume applied to the film do not affect the properties of the coating film (not shown). Show.

  By increasing the heat transfer rate given per unit area of the coating liquid as much as possible, the moisture content of the coating liquid coated on the belt-like support 2 is reduced from a moisture content of 95% or less of the limit moisture content to a desired residual moisture content. It is possible to perform the finish drying until it becomes a short time.

  In the second embodiment, the coating apparatus 1 having the drying apparatus 4 in which the lengths of the three drying chambers 11 that can independently control the drying conditions are equal to each other is used.

  In the first drying chamber 11 a according to the second embodiment, a coating liquid is applied to the hot air dryer that blows hot air in a direction opposite to the traveling direction of the belt-like support 2 and the coater 3 on the belt-like support 2. There is provided a hot air dryer that applies hot air to the belt-like support 2 at a right angle from the surface opposite to the coated surface.

  In the second drying chamber 11b in the second embodiment, hot air is applied at a right angle from the surface of the belt-like support 2 coated with the coating liquid by the coating machine 3 and from both sides of the opposite surface. A hot air dryer supported by hot air is provided.

  In the third drying chamber 11c in the second embodiment, hot air is applied at right angles from the surface of the belt-like support 2 on which the coating liquid is applied by the coating machine 3 and from both sides of the opposite surface. A hot air dryer supported by hot air is provided.

  Here, as for the heat transfer rate, it is desirable to obtain the heat transfer rate per unit area of the coating solution applied on the belt-like support 2, but actually the heat transfer rate per unit area of the coating solution is measured. Since this is difficult, in Embodiment 2, the heat transfer rate supplied by the dryer is determined by calculation.

Here, the specific drying conditions of the dryer used in Embodiment 2 will be described. In the first drying chamber 11 a, a hot air dryer that blows hot air in a direction opposite to the traveling direction of the belt-like support 2, and a surface on which the coating liquid is applied by the coating machine 3 on the belt-like support 2 Is provided with a hot air dryer that applies hot air to the belt-like support 2 at a right angle from the opposite side, and has a device width that is twice the coating width of the coating liquid applied on the belt-like support 2. The coating liquid was heated with hot air having a temperature of 80 ° C. and a wind speed of 1 m / s. The heat transfer rate supplied by the hot air dryer per unit area, which is obtained by calculation, is 2500 J / (m ² · s).

The hot air dryer in the second drying chamber 11b has a device width twice the coating width of the coating liquid applied on the belt-like support 2, and the hot air dryer has a temperature of 50 ° C. The amount of heat was applied to the coating solution by hot air having a wind speed of 1 m / s. The heat transfer rate supplied by the hot air dryer per unit area, which is obtained by calculation, is 1200 J / (m ² · s).

Further, the hot air dryer in the third drying chamber 11c has a device width twice the coating width of the coating liquid applied on the belt-like support 2, and the hot air dryer has a temperature of 80 ° C. The amount of heat was applied to the coating solution by hot air having a wind speed of 2 m / s. The heat transfer rate supplied by the hot air dryer per unit area, calculated by calculation, is 4500 J / (m ² · s).

  Here, the limit water content of the polarizable electrode liquid used in Embodiment 2 is 1.5, and the water content of the coating liquid in the first drying chamber 11a is 1.65 which is 110% of the limit water content. In the second drying chamber 11b, the moisture content of the coating solution is dried to 1.35 which is 90% of the limit moisture content, and the residual moisture content of the coating solution becomes 2% in the third drying chamber 11c. Drying was performed as follows.

(Embodiment 3)
Hereinafter, with respect to the coating apparatus and the drying method after coating the coating liquid on the continuously running belt-like support in the third embodiment of the present invention, only the differences from the first and second embodiments will be described with reference to the drawings. While explaining.

  In the third embodiment, the polarizable electrode solution, which is a coating solution applied by a die coater, which is a coating machine 3, is dried on an aluminum etching foil obtained by roughening aluminum, which is a belt-like support 2, by etching. The drying apparatus 4 used was the coating apparatus 1 having three drying chambers 11 capable of independently controlling the drying conditions.

  In the third embodiment, the length of the drying chamber 11 capable of independently controlling the drying conditions is the length of the first drying chamber 11a is 1/2 that of the drying device 4, and the second drying. The coating device 1 having the drying device 4 in which the length of the chamber 11b is 1/4 of the drying device 4 and the length of the third drying chamber 11c is 1/4 of the drying device 4 is used. It was.

  In the first drying chamber 11 a according to the third embodiment, the coating liquid is applied to the hot air dryer that blows hot air in the direction opposite to the traveling direction of the belt-like support 2 and the coater 3 on the belt-like support 2. A hot air dryer that applies hot air to the belt-like support 2 at a right angle from a surface opposite to the coated surface, and an infrared dryer above the belt-like support 2 are provided.

  In the second drying chamber 11b in the third embodiment, hot air is applied at right angles from the surface of the belt-like support 2 on which the coating liquid is applied by the coating machine 3 and both sides of the opposite surface. A hot air dryer supported by hot air is provided.

  In the third drying chamber 11c in the third embodiment, hot air is applied at right angles from the surface on which the coating liquid is applied by the coating machine 3 on the belt-like support 2 and from both sides of the opposite surface. A hot air dryer supported by hot air and an infrared dryer above the belt-like support 2 are provided.

  Here, as for the heat transfer rate, it is desirable to obtain the heat transfer rate per unit area of the coating solution applied on the belt-like support 2, but actually the heat transfer rate per unit area of the coating solution is measured. Since this is difficult, in Embodiment 3, the heat transfer rate supplied by the dryer is determined by calculation.

Here, the specific drying conditions of the dryer used in Embodiment 3 will be described. In the first drying chamber 11 a, a hot air dryer that blows hot air in a direction opposite to the traveling direction of the belt-like support 2, and a surface on which the coating liquid is applied by the coating machine 3 on the belt-like support 2 Are provided with a hot air dryer that applies hot air to the belt-like support 2 at right angles to the belt-like support 2 and an infrared dryer above the belt-like support 2, both of which are coated on the belt-like support 2. The apparatus width is twice the coating width of the coating liquid, and with those hot air dryers, hot air having a temperature of 80 ° C. and a wind speed of 1 m / s is applied to the belt-like support 2, and an infrared dryer is 350 Heating was applied to the coating solution by heating to ℃. The heat transfer rate supplied per unit area of the hot air dryer and the infrared dryer determined by calculation is 10000 J / (m ² · s).

The hot air dryer in the second drying chamber 11b has a device width twice the coating width of the coating liquid applied on the belt-like support 2, and the hot air dryer has a temperature of 50 ° C. The amount of heat was applied to the coating solution by hot air having a wind speed of 1 m / s. The heat transfer rate supplied by the hot air dryer per unit area, which is obtained by calculation, is 1200 J / (m ² · s).

In addition, the hot air dryer in the third drying chamber 11c and the infrared dryer provided above the belt-like support 2 have a device width that is twice the coating width of the coating liquid applied on the belt-like support 2. With the hot air dryer, heat is applied to the coating liquid by applying hot air at a temperature of 80 ° C. and a wind speed of 2 m / s to the belt-like support 2 and heating the infrared dryer to 350 ° C. It was. The heat transfer rate supplied per unit area in combination of the hot air dryer and the infrared dryer determined by calculation is 13000 J / (m ² · s).

  Here, the limit water content of the polarizable electrode solution used in Embodiment 3 is 1.5, and the water content of the coating solution in the first drying chamber 11a is 1.65 which is 110% of the limit water content. In the second drying chamber 11b, the moisture content of the coating solution is dried to 1.35 which is 90% of the limit moisture content, and the residual moisture content of the coating solution becomes 2% in the third drying chamber 11c. Drying was performed as follows.

(Embodiment 4)
Hereinafter, with respect to the coating apparatus and the drying method after coating the coating liquid on the continuously running belt-like support in the fourth embodiment of the present invention, the differences from the first embodiment, the second embodiment, and the third embodiment Only will be described with reference to the drawings.

  In the fourth embodiment, the polarizable electrode solution, which is a coating solution applied by a die coater, which is a coating machine 3, is dried on an aluminum etching foil obtained by roughening aluminum, which is a belt-like support 2, by etching. The drying apparatus 4 used was the coating apparatus 1 having six drying chambers 11 capable of independently controlling the drying conditions.

  Further, in the fourth embodiment, the coating apparatus 1 having the drying apparatus 4 in which the lengths of the six drying chambers 11 capable of independently controlling the drying conditions are equal to each other is used.

  Next, when the drying device 4 for drying the coating solution applied by the coating machine 3 on the belt-like support 2 has four or more drying chambers 11 capable of independently controlling the drying conditions. Will be described.

  First, how to separate the drying zones in the drying apparatus 4 having four or more drying chambers 11 capable of independently controlling the drying conditions will be described. First, the first drying zone is a drying chamber 11 that is continuous from the first drying chamber 11a, and the heat transfer rate per unit area of the coating solution is applied to the coating solution applied on the belt-like support 2. This is an aggregate of the drying chamber 11 that is equal to or higher than the heat transfer rate per unit area given to the coating liquid in the previous drying chamber 11.

  The second drying zone is a drying chamber 11 that is continuous from the final drying chamber 11 of the first drying zone, and per unit area of the coating liquid with respect to the coating liquid applied on the belt-like support 2. The continuous heat transfer rate applied to the first drying zone 11 is equal to or lower than the heat transfer rate per unit area given to the coating solution in the final drying chamber 11 of the first drying zone, and the coating solution in the drying chamber 11 is continuous. The heat transfer rate per unit area given to the drying chamber 11 is an aggregate of the drying chambers 11 that is equal to or lower than the heat transfer rate per unit area given to the coating liquid in the previous drying chamber 11.

  Further, the third drying zone is a drying chamber 11 continuous from the final drying chamber 11 of the second drying zone, and the heat transfer rate per unit area given to the coating liquid applied on the belt-like support 2. Is the aggregate of all the drying chambers 11 after the drying chamber 11 in the final drying chamber 11 of the second drying zone, which is equal to or higher than the heat transfer rate per unit area given to the coating liquid.

  In addition, about the drying chamber 11 of a 1st drying zone, the heat transfer rate per unit area given to the coating liquid apply | coated on the strip | belt-shaped support body 2 is intermittently applied in the previous drying chamber 11 in the coating liquid. Even if the drying chamber 11 that is equal to or lower than the heat transfer rate per unit area given to the coating chamber is included, the heat transfer rate per unit area given to the coating liquid is applied in the previous drying chamber 11 after the drying chamber 11. A drying chamber 11 having a heat transfer rate per unit area or higher given to the liquid is provided, and the heat transfer rate per unit area given to the coating liquid is one in the drying chamber 11 or the subsequent drying chamber 11. When the drying chamber 11 having a heat transfer rate per unit area or higher given to the coating liquid (not shown) in the previous drying chamber 11 is continuous, in the final drying chamber 11 of the continuous drying chamber 11. Limited moisture content of coating liquid after drying If the moisture content is in the range of 80% to 150%, the first drying chamber 11a to the drying chamber 11 where the moisture content of the coating solution is dried to a range of 80% to 150% of the critical moisture content is the first. Can be defined as the drying zone.

  Further, in the drying chamber 11 of the second drying zone, the heat transfer rate per unit area given to the coating solution applied on the belt-like support 2 is intermittently decreased in the previous drying chamber 11. Even if the drying chamber 11 is higher than the heat transfer rate per unit area given to the coating chamber, the heat transfer rate per unit area given to the coating solution is applied in the previous drying chamber 11 after the drying chamber 11. A drying chamber 11 having a heat transfer rate per unit area or less given to the liquid is provided. In the drying chamber 11 or the subsequent drying chamber 11, the heat transfer rate per unit area given to the coating solution is one. When the drying chamber 11 that is equal to or lower than the heat transfer rate per unit area applied to the coating liquid in the previous drying chamber 11 is continuous, the coating after the end of drying in the final drying chamber 11 of the continuous drying chamber 11 is performed. The water content of the liquid is 9 If it is% or less, from the last drying chamber 11 continuous with the final drying chamber 11 of the first drying zone to the drying chamber 11 where the moisture content of the coating liquid is dried to 95% or less of the limit moisture content Can be defined as the second drying zone.

  Then, when the drying apparatus 4 for drying the coating liquid applied by the coating machine 3 on the belt-like support 2 has four or more drying chambers 11 capable of independently controlling the drying conditions. A drying method will be described.

  First, there are four or more drying chambers 11 capable of independently controlling the drying conditions, and in the drying device 4 that can be divided into three drying zones, the first drying zone has a belt-like support. It is desirable to perform drying for a period until the moisture content of the coating solution applied on the body 2 by the coating machine 3 is in the range of 80% to 150% of the critical moisture content. In addition, the type of dryer used at that time is at least one of a dryer using a mechanism based on conduction heat transfer, a dryer using a mechanism based on convection heat transfer, and a dryer using a mechanism based on radiant heat transfer. More than one dryer can be used.

  In the first drying zone, the belt-like support 2 is in a drying period in which the moisture content of the coating solution applied onto the belt-like support 2 by the coating machine 3 is in the range of 80% to 150% of the critical moisture content. It is desirable to increase the heat transfer rate applied per unit area of the coating liquid as much as possible with respect to the above coating liquid.

  To increase the heat transfer rate applied per unit area of the coating liquid as much as possible to the coating liquid on the belt-like support 2 is different depending on the type of the target coating film, although the appropriate temperature and air volume are different. It is shown that the heat transfer rate given per unit area of the coating liquid is increased by the high temperature and large air volume within the range in which the temperature and the air volume applied to the film do not affect the properties of the coating film.

  Initial drying until the water content of the coating liquid applied on the belt-like support 2 is in the range of 80% to 150% of the critical water content by increasing the heat transfer rate per unit area of the coating liquid as much as possible. Can be performed in a short time.

  In addition, in the drying apparatus 4 having four or more drying chambers 11 that can independently control the drying conditions and can be divided into three drying zones, the second drying zone has a belt-like support. Drying for a period of time until the moisture content of the coating solution applied on the body 2 by the coating machine 3 reaches a moisture content of not more than 80% and not more than 150% of the limit moisture content to not more than 95% of the limit moisture content. desirable.

  The type of dryer used at that time is at least one of a dryer using a mechanism based on conduction heat transfer, a dryer using a mechanism based on convection heat transfer, and a dryer using a mechanism based on radiation heat transfer. The dryer can be used. In the second drying zone, it is more desirable to dry a period in which the moisture content of the coating liquid is the critical moisture content.

  Further, in the second drying zone, the water content of the coating liquid applied on the belt-like support 2 by the coating machine 3 is in the range of 80% to 150% of the critical moisture content, and the water content of 95% or less of the critical moisture content. The heat transfer rate given per unit area of the coating liquid to the coating liquid on the belt-like support 2 during the drying period until the rate reaches is the coating liquid on the surface of the coating liquid coated on the belt-like support 2 It is desirable to set the evaporation rate of the solvent therein to be equal to or lower than the diffusion rate of the solvent in the coating solution.

  The heat transfer rate given per unit area of the coating solution to the coating solution on the belt-like support 2 is such that the evaporation rate of the solvent in the coating solution on the surface of the coating solution is less than the diffusion rate of the solvent in the coating solution. If there are four or more drying chambers 11 capable of independently controlling the drying conditions of the coating liquid applied on the belt-like support 2, it is divided into three drying zones. By drying with the drying device 4 that can be applied, it is possible to obtain a coating film that is soft, has no cracks or peeling, and has a smooth surface.

  In the drying apparatus 4 that has four or more drying chambers 11 that can independently control the drying conditions and can be divided into three drying zones, in the third drying zone, the belt-like support 2 It is desirable to perform drying for a period until the moisture content of the coating liquid applied by the coating machine 3 reaches a desired residual moisture content from a moisture content of 95% or less of the critical moisture content.

  In addition, the type of dryer used at that time is at least one of a dryer using a mechanism based on conduction heat transfer, a dryer using a mechanism based on convection heat transfer, and a dryer using a mechanism based on radiant heat transfer. More than one dryer can be used.

  Further, in the third drying zone, in the period from the moisture content of 95% or less of the moisture content of the coating solution applied on the belt-like support 2 by the coating machine 3 to the desired residual moisture content, the belt-like support It is desirable to increase the heat transfer rate given per unit area of the coating liquid as much as possible with respect to the coating liquid on 2.

  To increase the heat transfer rate applied per unit area of the coating liquid as much as possible to the coating liquid on the belt-like support 2 is different depending on the type of the target coating film, although the appropriate temperature and air volume are different. It is shown that the heat transfer rate given per unit area of the coating liquid is increased by the high temperature and large air volume within the range in which the temperature and the air volume applied to the film do not affect the properties of the coating film.

  By increasing the heat transfer rate given per unit area of the coating liquid as much as possible, the moisture content of the coating liquid coated on the belt-like support 2 is reduced from a moisture content of 95% or less of the limit moisture content to a desired residual moisture content. It is possible to perform the finish drying until it becomes a short time.

  As shown in FIG. 2, the drying apparatus 4 according to the fourth embodiment of the present invention has six drying chambers, from the first drying chamber 11a to the sixth drying chamber 11f, respectively. Are a hot air dryer that blows hot air in a direction opposite to the traveling direction of the belt-like support 2 and a belt-like shape from a surface opposite to the surface on which the coating liquid is applied by the coating machine 3 on the belt-like support 2. A hot air drier that applies hot air to the support 2 at a right angle is provided.

  The second drying chamber 11b is coated with a coating liquid by a hot air dryer that blows hot air in a direction opposite to the traveling direction of the belt-like support 2 and a coater 3 on the belt-like support 2. A hot air dryer that applies hot air to the belt-like support 2 at a right angle from a surface opposite to the surface of the belt-like support 2 and an infrared dryer above the belt-like support 2 are provided.

  Further, in the third drying chamber 11c, hot air is applied at right angles from the surface on which the coating liquid is applied by the coating machine 3 on the belt-like support 2 and from both sides of the opposite surface, and the belt-like support 2 is supported by hot air. It has a hot air dryer.

  Further, hot air is applied to the fourth drying chamber 11d at a right angle from the surface on which the coating liquid is applied by the coating machine 3 on the belt-like support 2 and from both sides of the opposite surface, and the belt-like support 2 is supported by the hot air. It has a hot air dryer.

  Further, hot air is applied to the fifth drying chamber 11e at a right angle from the surface on which the coating liquid is applied by the coating machine 3 on the belt-like support 2 and from both sides of the opposite surface, and the belt-like support 2 is supported by the hot air. It has a hot air dryer.

  In addition, hot air is applied to the sixth drying chamber 11f at a right angle from the surface on which the coating liquid is applied by the coating machine 3 on the belt-like support 2 and from both sides of the opposite surface, and the belt-like support 2 is supported by the hot air. And an infrared dryer above the belt-like support 2.

  In the fourth embodiment, the six drying chambers 11 are divided into the following three drying zones. First, the first drying zone is the first drying chamber 11a and the second drying chamber 11b, and the second drying zone is from the third drying chamber 11c to the fifth drying chamber 11e, The third drying zone is a sixth drying chamber 11f.

  Here, as for the heat transfer rate, it is desirable to obtain the heat transfer rate per unit area of the coating solution applied on the belt-like support 2, but actually the heat transfer rate per unit area of the coating solution is measured. Since this is difficult, in Embodiment 4, the heat transfer rate supplied by the dryer is determined by calculation.

Here, specific drying conditions of the dryer used in Embodiment 4 will be described. In the first drying chamber 11a, a hot air dryer that blows hot air in a direction opposite to the traveling direction of the belt-like support 2 and a coating liquid is applied on the belt-like support 2 by the coating machine 3. A hot-air dryer that applies hot air to the belt-like support 2 at a right angle from a surface opposite to the surface is provided, both of which are devices that are twice the coating width of the coating liquid applied on the belt-like support 2 The coating liquid was heated with hot air having a temperature of 80 ° C. and a wind speed of 1 m / s. The heat transfer rate supplied by the hot air dryer per unit area, which is obtained by calculation, is 2500 J / (m ² · s).

In the second drying chamber 11b, a hot air dryer that blows hot air in a direction opposite to the traveling direction of the belt-like support 2 and a coating liquid was applied on the belt-like support 2 by the coating machine 3. A hot air dryer that applies hot air to the belt-like support 2 at a right angle from a surface opposite to the surface, and an infrared dryer above the belt-like support 2, both of which are provided on the belt-like support 2 It has a device width that is twice the coating width of the applied coating liquid, and with those hot air dryers, hot air having a temperature of 80 ° C. and a wind speed of 2.5 m / s is applied to the belt-like support 2, and infrared rays A heating amount was given to the coating solution by heating the dryer to 500 ° C. The heat transfer rate supplied per unit area of the hot air dryer and infrared dryer determined by calculation is 24000 J / (m ² · s).

Further, the hot air dryer in the third drying chamber 11c has a device width that is twice the coating width of the coating liquid applied on the belt-like support 2, and the hot air dryer has a temperature of 50 ° C. The amount of heat was applied to the coating solution with hot air having a wind speed of 1.5 m / s. The heat transfer rate supplied by the hot air dryer per unit area, which was obtained by calculation, is 1700 J / (m ² · s).

The hot air dryer in the fourth drying chamber 11d has a device width that is twice the coating width of the coating liquid applied on the belt-like support 2, and the hot air dryer has a temperature of 50 ° C. The amount of heat was applied to the coating solution by hot air having a wind speed of 1.2 m / s. The heat transfer rate supplied per unit area by the hot air dryer determined by calculation is 1400 J / (m ² · s).

The hot air dryer in the fifth drying chamber 11e has a device width that is twice the coating width of the coating liquid applied on the belt-like support 2, and the hot air dryer has a temperature of 50 ° C. The amount of heat was applied to the coating solution by hot air having a wind speed of 1 m / s. The heat transfer rate supplied by the hot air dryer per unit area, which is obtained by calculation, is 1200 J / (m ² · s).

Further, the hot air dryer in the sixth drying chamber 11f and the infrared dryer provided above the belt-like support 2 have a device width that is twice the coating width of the coating liquid applied on the belt-like support 2. With the hot air dryer, heat was applied to the coating solution by applying hot air having a temperature of 80 ° C. and a wind speed of 2 m / s to the belt-like support 2 and heating the infrared dryer to 500 ° C. . The heat transfer rate supplied per unit area in combination of the hot air dryer and the infrared dryer determined by calculation is 23000 J / (m ² · s).

  Here, the limit water content of the polarizable electrode liquid used in the fourth embodiment is 1.5, and the water content of the coating liquid in the first drying zone is 1.65 which is 110% of the limit water content. Dried and dried in the second drying zone until the moisture content of the coating solution is 1.35 which is 90% of the critical moisture content, and dried in the third drying zone so that the residual moisture content of the coating solution is 2%. Went.

  Here, an evaluation method, detailed apparatus conditions, and operation conditions of the polarizable electrode 12 obtained in the first to fourth embodiments will be described.

  The obtained polarizable electrode 12 is slid on the polarizable electrode 12 by an adhesion evaluation device comprising the presser 13, the electrode support base 14, the round bars 15 and 16, and the weight 17 shown in FIG. Is evaluated according to the degree of occurrence of peeling and cracks, and after the evaluation, 5 is the case where no peeling or cracking occurs in the polarizable electrode 12, and the polarizable electrode layer is peeled from the current collector as the belt-like support 2 The evaluation was performed with 1 being the case and 2 to 4 between them.

  First, Example 1 according to Embodiment 1 will be described.

Example 1
Application and drying are performed at a coating speed of 2 m / min using the coating apparatus 1 including the drying apparatus 4 in which the length of the first drying chamber 11a is 1 m and the length of the second drying chamber 11b is 4 m. went.

  Example 2 according to the second embodiment will be described.

(Example 2)
Coating and drying were performed at a coating speed of 2 m / min using the coating apparatus 1 including the drying apparatus 4 having three drying chambers 11 having a length of the drying chamber 11 of 1 m.

  Example 3 according to Embodiment 3 will be described.

(Example 3)
The coating apparatus 1 provided with the drying apparatus 4 in which the length of the first drying chamber 11a is 1 m, the length of the second drying chamber 11b is 0.5 m, and the length of the third drying chamber 11c is 0.5 m. Was applied and dried at a coating speed of 2 m / min.

  Example 4 according to Embodiment 4 will be described.

Example 4
Coating and drying were performed at a coating speed of 2 m / min using the coating apparatus 1 including the drying apparatus 4 having six drying chambers 11 with the length of the drying chamber 11 being 0.3 m.

(Conventional example 1)
Coating and drying were performed at a coating speed of 2 m / min using the coating apparatus 1 including the drying apparatus 4 having three drying chambers 11 with the length of the drying chamber 11 being 0.7 m.

In the first drying chamber 11a, a hot air dryer that blows hot air in a direction opposite to the traveling direction of the belt-like support 2 and a coating liquid is applied on the belt-like support 2 by the coating machine 3. A hot-air dryer that applies hot air to the belt-like support 2 at a right angle from a surface opposite to the surface is provided, both of which are devices that are twice the coating width of the coating liquid applied on the belt-like support 2 The coating liquid was heated with hot air having a temperature of 80 ° C. and a wind speed of 2 m / s. The heat transfer rate supplied by the hot air dryer per unit area, calculated by calculation, is 4500 J / (m ² · s).

Further, in the second drying chamber 11b, hot air is applied at right angles from the surface on which the coating liquid is applied by the coating machine 3 on the belt-like support 2 and from both sides of the opposite surface, and the belt-like support 2 is heated by hot air. A supporting hot air dryer is provided, and the hot air dryer has a device width that is twice the coating width of the coating liquid applied on the belt-like support 2, and has a temperature of 90 ° C. and a wind speed of 2 m / second. The amount of heat was applied to the coating solution by hot air of s. The heat transfer rate supplied by the hot air dryer per unit area, which is obtained by calculation, is 5400 J / (m ² · s).

Further, in the third drying chamber 11c, hot air is applied at right angles from the surface on which the coating liquid is applied by the coating machine 3 on the belt-like support 2 and from both sides of the opposite surface, and the belt-like support 2 is heated by hot air. A supporting hot air dryer is provided, and the hot air dryer has a device width that is twice the coating width of the coating liquid applied on the belt-like support 2, and has a temperature of 100 ° C. and a wind speed of 2 m / second. The amount of heat was applied to the coating solution by hot air of s. The heat transfer rate supplied by the hot air dryer per unit area, calculated by calculation, is 6200 J / (m ² · s).

  Here, the limit moisture content of the polarizable electrode solution used in Conventional Example 1 is 1.5, and the moisture content of the coating solution is dried to 1.65 which is 110% of the limit moisture content in the first drying chamber 11a. In the second drying chamber 11b, the moisture content of the coating solution is dried to 0.9 which is 60% of the limit moisture content, and the residual moisture content of the coating solution is 2% in the third drying chamber 11c. Drying was performed.

  In the following (Table 1), the evaluation result of the adhesiveness of the polarizable electrode 12 produced by these Examples 1 to 4 and Conventional Example 1 is shown.

  Examples 1 to 4 which are examples of the present invention and Conventional Example 1 are compared based on the results shown in Table 1.

  When the adhesion of the polarizable electrode produced in Examples 1 to 4 and the adhesion of the polarizable electrode produced in Conventional Example 1 are compared, it is clear that the polarizable electrodes produced in Examples 1 to 4 Good adhesion.

  This is because when the water content of the polarizable electrode liquid is 1.5, which is the critical water content, the rate of water evaporation on the surface of the polarizable electrode is low because the heat transfer rate applied to the polarizable electrode was small. This was because the inside of the polarizable electrode was uniformly dried because it was slower than the internal water diffusion rate.

  Next, Examples 1 to 4 which are examples of the present invention will be compared from the results shown in (Table 1).

  When Example 1 is compared with Examples 2 to 4, Example 2 to Example 4 are shorter in length than the example 1 and the drying time is shorter. This is because in Examples 2 to 4 there are three or more drying chambers, so that the water content of the polarizable electrode liquid is dried in the vicinity of the limit water content. This is because the finishing drying time can be shortened by providing the third drying chamber or the third drying zone having a higher heat transfer rate after the second drying chamber or the second drying zone.

  When Example 2 is compared with Example 3 and Example 4, Example 3 and Example 4 have a shorter overall drying apparatus and a shorter drying time than Example 2. This is because, in Example 3 and Example 4, the first drying chamber or the first drying zone, and the third drying chamber or the third drying zone, using an infrared dryer that is a dryer with a radiant heat transfer mechanism, This is because the initial drying time and the finishing drying time can be shortened.

  When Example 3 and Example 4 are compared, Example 4 has a shorter overall drying apparatus length and drying time than Example 3. This is because Example 4 has a larger number of drying chambers than Example 3, so that the drying conditions can be set more finely.

  When the coating apparatus and the drying method after coating the coating liquid of the present invention are performed, it has the effect of being able to obtain a coating film that is soft, free of cracks and peeling, and has a smooth surface by drying in a short time. Use of the coating film obtained by the method is useful because it can prevent occurrence of troubles in the post-process and can obtain a coating film having good characteristics.

Schematic of a coating apparatus in an embodiment of the present invention Schematic of a coating apparatus in an embodiment of the present invention Schematic diagram of a polarizable electrode adhesion evaluation device

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Coating device 2 Band-shaped support body 3 Coating machine 4 Drying device 5 Unwinding roll 6 Winding roll 7 Backup roll 8, 9, 10 Roll 11 Drying chamber 11a 1st drying chamber 11b 2nd drying chamber 11c 3rd drying Chamber 11d Fourth drying chamber 11e Fifth drying chamber 11f Sixth drying chamber 11x Final drying chamber 12 Polarized electrode 13 Presser 14 Electrode support base 15, 16 Round bar 17 Weight

Claims (6)

In the manufacturing method of the coating film which has an application process which applies a coating liquid on a beltlike support, and then a drying process which dries a beltlike support on which the application liquid was applied in a drying room, the drying process Is dried until reaching the limit water content which is the water content of the coating liquid at the time when the diffusion rate in the coating liquid on almost the entire surface of the coating liquid is smaller than the evaporation rate of the liquid from the liquid surface. The manufacturing method of the coating film characterized by having a 1st drying process and the 2nd drying process which dries after that, and a heat transfer rate is higher in the said 1st drying process than the said 2nd drying process. In the manufacturing method of the coating film which has an application process which applies a coating liquid on a beltlike support, and then a drying process which dries a beltlike support on which the application liquid was applied in a drying room, the drying process Is dried until reaching the limit water content which is the water content of the coating liquid at the time when the diffusion rate in the coating liquid on almost the entire surface of the coating liquid is smaller than the evaporation rate of the liquid from the liquid surface. A first drying step; a second drying step for drying the second drying step; and a third drying step following the second drying step, wherein the first drying step and the third drying step are the second drying step. A method for producing a coating film, wherein the heat transfer rate is higher than that of the coating film. In a coating apparatus including an application unit that applies a coating liquid on a belt-like support and a drying unit that dries the belt-like support on which the coating liquid is applied in a plurality of drying chambers, the drying chamber includes the coating A first drying chamber that dries until the limit moisture content, which is the moisture content of the coating solution at a time point when the diffusion rate of the coating solution on almost the entire surface of the solution is smaller than the evaporation rate of the solution from the surface of the solution. And a second drying chamber for drying the subsequent chambers, wherein the first drying chamber has a higher heat transfer rate than the second drying chamber. The coating apparatus according to claim 3, wherein the first drying chamber has a length of 1/10 or more with respect to the length of all the drying chambers. In a coating apparatus including an application unit that applies a coating liquid on a belt-like support and a drying unit that dries the belt-like support on which the coating liquid is applied in a plurality of drying chambers, the drying chamber includes the coating A first drying chamber that dries until the limit moisture content, which is the moisture content of the coating solution at a time point when the diffusion rate of the coating solution on almost the entire surface of the solution is smaller than the evaporation rate of the solution from the surface of the solution. And a second drying chamber that performs subsequent drying, and a third drying chamber that follows the second drying chamber, and the heat transfer rate applied to the coating liquid in the first drying chamber and the third drying chamber is A coating apparatus having a heat transfer rate higher than that applied to the coating solution in the second drying chamber. The length of the first drying chamber is 1/10 or more with respect to the length of all drying chambers, and the length of the second drying chamber is 4/5 or less with respect to the length of all drying chambers. The coating apparatus according to claim 5, wherein the length of the third drying chamber is 1/10 or more with respect to the length of all the drying chambers.

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